JP6217182B2 - Driving force transmission structure and optical instrument - Google Patents

Description

  The present invention relates to a driving force transmission structure and an optical apparatus.

Conventionally, a gear train has been used as a driving force transmission mechanism (see Patent Document 1).
On the other hand, for example, there is a camera in which a lens group is driven by an ultrasonic motor. Such a camera uses a gear train as a structure for transmitting the rotational force of an ultrasonic motor to a lens group. However, in the gear train, an audible sound may be generated due to contact between the gear teeth when the gears mesh with each other. In recent years, there are many cameras that can shoot not only still images but also moving images. In such cameras that can shoot moving images, there is a possibility that this audible sound may be recorded at the time of moving image shooting.

JP 2002-86884 A

  It is an object of the present invention to provide a driving force transmission structure and an optical apparatus with a quiet driving sound.

  The present invention solves the above problems by the following means.

The invention according to claim 1 is a driving force transmission structure for transmitting a driving force generated by the actuator from an output shaft of the actuator to a driven body, and an output roller attached to the output shaft of the actuator; A plurality of rollers including a driven member-side roller in contact with the driven member, wherein the plurality of rollers are arranged at positions where output shafts are different from each other in the first direction, A driving force transmission in which a force in the first direction is applied to the output shaft of the first roller, and a force in a second direction opposite to the first direction is applied to the output shaft of the second roller adjacent to the first roller. Structure.
According to a second aspect of the present invention, in the driving force transmission structure according to the first aspect, the plurality of rollers have a plurality of distances from the rotation center to the outer periphery when the driving force is transmitted by contacting each other. A driving force transmission structure characterized by being equal to a pitch circle radius of the gear when the driving force is transmitted from the actuator to the driven body by a gear train including a gear.
The invention according to claim 3 is the driving force transmission structure according to claim 1 or 2 , wherein the outer periphery of the roller is a rubber member.
A fourth aspect of the present invention is the driving force transmission structure according to any one of the first to third aspects , wherein the plurality of rollers generate a vertical drag generated at a contact portion between the rollers adjacent to each other. A driving force transmission structure characterized in that a pressing mechanism that applies force in the increasing direction is provided .
The invention described in 請 Motomeko 5 is an optical device including the driving force transmission structure according to any one of claims 1 to 4.

  ADVANTAGE OF THE INVENTION According to this invention, a driving force transmission structure and optical apparatus with a quiet driving sound can be provided.

1 is a conceptual configuration diagram of a camera having a driving force transmission structure according to a first embodiment. It is the figure which looked at the driving force transmission mechanism of 1st Embodiment from the direction perpendicular | vertical with respect to an optical axis. It is the figure which looked at the driving force transmission mechanism of 1st Embodiment from the top. It is the figure which looked at the driving force transmission mechanism of 2nd Embodiment from the direction perpendicular | vertical with respect to an optical axis. It is the figure which looked at the driving force transmission mechanism of 3rd Embodiment of this invention from upper direction. It is the figure which showed the driving force transmission mechanism of the deformation | transformation form of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure shown below is provided with an XYZ orthogonal coordinate system for ease of explanation and understanding. In this coordinate system, the direction toward the left side as viewed from the photographer at the position of the camera when the photographer shoots a horizontally long image with the optical axis A being horizontal (hereinafter referred to as a normal position) is defined as the X plus direction. Further, the direction toward the upper side in the normal position is defined as the Y plus direction. Further, the direction toward the subject at the normal position is defined as the Z plus direction.

(First embodiment)
FIG. 1 is a conceptual configuration diagram of the camera 1 that transmits the driving force of the ultrasonic motor 10 to the lens 31 by the driving force transmission structure of the first embodiment of the present invention.
The camera 1 includes a camera body 2 having an image sensor 4 and a lens barrel 3 having a lens 31.

The lens barrel 3 is an interchangeable lens that can be attached to and detached from the camera body 2. In the present embodiment, the lens barrel 3 is an interchangeable lens. However, the present invention is not limited to this. For example, the lens barrel 3 may be a lens barrel integrated with the camera body.
The lens barrel 3 includes a lens 31, a cam barrel 32, and an ultrasonic motor 10 that drives the lens 31 that is a focusing lens during the focusing operation of the camera 1.
In the present embodiment, the ultrasonic motor 10 is used as an actuator for driving the lens 31, but the present invention is not limited to this, and other types of motors such as a DC motor may be used.

  The rotational force of the ultrasonic motor 10 is transmitted to the cam cylinder 32 via the rubber roller row 5. The lens 31 is held by a cam cylinder 32 and is moved and driven in the optical axis direction (Z-axis direction) by the ultrasonic motor 10 to perform focus adjustment. In addition to the lens 31, the lens barrel 3 includes a lens group (not shown) that constitutes an imaging optical system.

  In the camera 1, a subject image is formed on the imaging surface of the imaging element 4 in the camera body 2 by a lens group including a lens 31 provided in the lens barrel 3 in FIG. 1. Then, the imaged subject image is converted into an electric signal by the image pickup device 4, and image data is obtained by A / D converting the signal.

FIG. 2 is a view of the driving force transmission mechanism of the first embodiment viewed from a direction perpendicular to the optical axis (Z direction). FIG. 3 is a view of the driving force transmission mechanism of the first embodiment as viewed from above (Y plus side).
As shown in the figure, the roller row 5 is attached to the output shaft 11 of the ultrasonic motor 10, a first roller 51 that rotates together with the output shaft 11, a second roller 52 that contacts the first roller 51, and a second roller And a third roller 53 in contact with 52. The third roller 53 is in contact with the cam cylinder 32.

The first roller 51, the second roller 52, and the third roller 53 are provided with layers of rubber materials 51a, 52a, and 53a only near the surface of the cylindrical base material. A layer of rubber material 32 a is also provided on the outer periphery of the cam cylinder 32.
The rubber material is preferably fluororubber, chloroprene rubber, urethane rubber, nitrile rubber, ethylene butadiene rubber, acrylic rubber or the like because of superior wear resistance and mechanical strength. Further, fiber reinforced rubber may be used for high load environments. The base material portion may be a separate member (resin, metal, high hardness rubber, ceramics, etc.) having high hardness.
In the present embodiment, the example in which the rubber material is provided on the surface (outer periphery) of the cylindrical base material as described above has been described. However, the present invention is not limited thereto, and the base material portion is also the same rubber material as the surface. May be formed.

In addition, the surface states of the first roller 51, the second roller 52, and the third roller 53 are preferably set to the surface shape of the ideal cylindrical side surface for the purpose of ensuring wear resistance, mechanical strength, and quietness. And it is better that the surface is less sticky. However, in the case of a light load driving roller, a layer in which fine porous material is distributed on the surface may be provided in order to provide sound absorption.
Further, in order to increase the shear strength of the roller surface, the base material may be made of fiber reinforced rubber, and may be covered with a rubber layer of another member having a sound absorbing property on the surface.
In order to increase the shear strength of the roller surface, the base material may be a rubber having a high rubber hardness and may be covered with a rubber layer having a low rubber hardness, which is a separate member having a sound absorbing property on the surface.

As described above, the output shaft 11 of the ultrasonic motor 10 penetrates through the center of the first roller 51 so that it cannot rotate. Further, the center shafts 52b and 53b penetrate through the centers of the second roller 52 and the third roller 53, respectively, so as not to rotate with each other.
The output shaft 11 and the center shafts 52b and 53b extend from the Z minus side to the Z plus side through the first roller 51, the second roller 52, and the third roller 53, respectively.

  A spring member is attached between the central axes of the rollers that are in contact with each other, and is biased so that the central axes attract each other. The spring members are arranged at two locations on the Z minus side and the Z plus side with the roller interposed therebetween. However, the present invention is not limited to this, and either the Z minus side or the Z plus side may be used.

  That is, the spring member 54a is attached in the Z plus direction between the output shaft 11 of the first roller 51 and the central shaft 52b of the second roller 52 that are in contact with each other, with the first roller 51 and the second roller 52 interposed therebetween. The spring member 54b is attached in the Z minus direction.

  A spring member 55a is attached in the Z plus direction between the central shaft 52b of the second roller 52 and the central shaft 53b of the third roller 53 that are in contact with each other, with the second roller 52 and the third roller 53 interposed therebetween. The spring member 55b is attached in the Z minus direction.

  The spring members 54a, 54b, 55a, and 55b are attached to the respective shafts so as not to prevent the rotation of the shafts 51b, 52b, and 53b to which the spring members 54a, 54b, 55a, and 55b are attached.

Here, as shown in FIG. 2, in a state where the rollers 51, 52, 53 are pressed against each other by the spring members 54a, 54b, 55a, 55b, from the center of each roller 51, 52, 53 to the outer periphery of the contact portion. , R1, R2, R3.
The distances R1, R2, and R3 are slightly smaller than the radii of the rollers 51, 52, and 53 themselves because the rubber members 51, 52, and 53 are pressed against each other and the rubber member is elastically deformed. It may be small.
In the present embodiment, each of the rollers 51, 52, and 53 has a pitch circle of each gear when the distances R1, R2, and R3 are configured by a gear train having the same function as the driving force transmission structure of the present embodiment. It is configured to be equal to the radius of the (module circle).

  According to the present embodiment, the adjacent rollers (first roller 51 and second roller 51) depend on the spring force of the spring members 54a, 54b, 55a, 55b and the rigidity of the shaft (output shaft 51b, center shaft 52b, 53b) itself. 52, and the second roller 52 and the third roller 53) are pressed against each other. As a result, the vertical drag at the contact portions of the rollers 51, 52, and 53 increases, so that slippage is unlikely to occur. Therefore, the driving force of the ultrasonic motor 10 is transmitted from the first roller 51 to the cam cylinder 32 via the second roller 52 and the third roller 53 with a small loss.

  Moreover, in this embodiment, since the rubber roller is used for transmission of the driving force of the ultrasonic motor 10, that is, no gear train is used, no audible sound is generated when the gears mesh with each other. For this reason, noise reduction of the camera 1 is achieved.

(Second Embodiment)
FIG. 4 is a view of the driving force transmission mechanism according to the second embodiment of the present invention viewed from a direction perpendicular to the optical axis. In addition, the same code | symbol is attached | subjected to the part similar to 1st Embodiment, and the description is abbreviate | omitted.
As shown in the figure, the second embodiment is different from the first embodiment in that no spring member is provided between the central axes of the rollers that are in contact with each other. The spring member connecting the two portions is provided so as to increase the pressing force (vertical drag, force in the normal direction between the surfaces) of the contact portion between the rollers.

That is, as shown in FIG. 4, the lens barrel 3 of this embodiment includes an upper fixing portion 3U and a lower fixing portion 3D. A spring member 56 is provided between the output shaft 11 and the lower fixing portion 3D, and the output shaft 11 is urged toward the lower fixing portion 3D.
Further, a spring member 57 is provided between the central shaft 52b and the upper fixed portion 3U, and the central shaft 52b is biased toward the upper fixed portion 3U.
Further, a spring member 58 is provided between the central shaft 53b and the lower fixing portion 3D, and the central shaft 53b is biased toward the lower fixing portion 3D.

  Thereby, when each roller 51,52,53 of the roller row | line | column 5 is seen with two mutually adjacent rollers, the roller below is pulled upwards and the roller above is pulled downwards.

That is, in the case of the first roller 51 and the second roller 52, the upper first roller 51 is pulled downward, and the lower second roller 52 is pulled upward.
In the case of the second roller 52 and the third roller 53, the lower second roller 52 is pulled upward, and the upper third roller 53 is pulled downward.

Here, the first roller 51 is placed on the upper part of the second roller 52, and the contact portion between them is arranged at the lower part of the first roller and the upper part of the second roller.
Since the first roller 51 is pulled downward and the second roller 52 is pulled upward, the force of the spring members 56 and 57 causes the vertical drag at the contact portion between the first roller 51 and the second roller 52. Increases and slip decreases.

The second roller 52 is placed below the third roller 53, and the contact portion between them is arranged above the second roller and below the third roller.
Since the second roller 52 is pulled upward and the third roller 53 is pulled downward, the normal force at the contact portion between the second roller 52 and the third roller 53 is caused by the force of the spring members 56 and 58. Increases and slip decreases.

Therefore, the driving force of the ultrasonic motor 10 is transmitted from the first roller 51 to the cam cylinder 32 via the second roller 52 and the third roller 53 with a small loss.
Also in this embodiment, since the gear train is not used using the rubber roller for transmitting the driving force of the ultrasonic motor 10, no audible sound is generated when the gears mesh with each other. For this reason, noise reduction of the camera 1 is achieved.

(Third embodiment)
FIG. 5 is a view of the driving force transmission mechanism of the third embodiment of the present invention as viewed from above. Also in the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The third embodiment is different from the first embodiment in that each of the rollers 51, 52, and 53 has a truncated cone shape (taper shape).
The first roller 51 and the third roller 53 are arranged so that the upper bottom side is the Z plus side. The second roller 52 is disposed so that the lower bottom side is the Z plus side.
Further, the surface state of these rollers 51, 52, 53 is preferably the surface shape of the side surface of the ideal truncated cone for the purpose of wear resistance, ensuring mechanical strength, and quietness as in the first embodiment. .
In the present embodiment, the spring members 61, 62, and 63 are inserted through the respective shafts 11, 52b, and 53b to urge the rollers 51, 52, and 53 from the lower bottom side to the upper bottom side, respectively.

  That is, the spring member 61 is inserted in the Z plus direction of the output shaft 11 of the first roller 51. One end on the Z minus side of the spring member 61 is attached to the upper bottom side of the first roller 51 so as not to prevent the rotation of the first roller 51, and the other end is a fixing portion provided on the Z plus side of the roller 51. The first roller 51 is urged toward the fixed portion 3F.

  A spring member 62 is inserted in the Z plus direction of the central shaft 52b of the second roller 52. One end on the Z minus side of the spring member 62 is attached to the upper bottom side of the second roller 52 so as not to prevent the rotation of the second roller 52, and the other end is fixed to the fixing portion 3F. It is energized in the direction away from the fixed portion 3F.

  A spring member 63 is inserted in the Z plus direction of the central shaft 53 b of the third roller 53. One end on the Z minus side of the spring member 63 is attached to the upper bottom side of the third roller 53 so as not to prevent the rotation of the third roller 53, and the other end is fixed to the fixing portion 3F. It is biased toward the fixed portion 3F.

Also in this embodiment, adjacent rollers are pressed against each other by the force of the spring members 61, 62, and 63. This increases the vertical drag at the contact portion of each roller, reducing slippage.
Therefore, the driving force of the ultrasonic motor 10 is transmitted from the first roller 51 to the cam cylinder 32 via the second roller 52 and the third roller 53 with a small loss.
Moreover, in this embodiment, since the gear train is not used using a rubber roller for transmission of the driving force of the ultrasonic motor 10, no audible sound is generated when the gears mesh with each other. For this reason, noise reduction of the camera 1 is achieved.

(Deformation)
FIG. 6 is a view showing a modification of the first embodiment. As shown in the figure, a dummy roller 70 is provided at a point-symmetrical position across the output shaft 11 and the direction in which the second roller 52 is disposed on the outer periphery of the first roller 51 so that the first roller 51 is pressed. May be.
According to this embodiment, it is possible to prevent the output shaft 11 from escaping when rotation is started and to prevent the vertical drag from being lowered.

  1: camera, 3: lens barrel, 3D: lower fixing part, 3F: fixing part, 3U: upper fixing part, 5: roller train, 10: ultrasonic motor, 11: output shaft, 32: cam cylinder, 32a: Rubber material, 51: first roller, 51a, 52a, 53a: rubber material, 51b: output shaft, 52: second roller, 52b, 53b: central shaft, 53: third roller, 54a, 54b, 55a, 55b, 56, 57, 58, 61, 62, 63: Spring member, 70: Dummy roller

Claims (5)

A driving force transmission structure for transmitting a driving force generated by the actuator from an output shaft of the actuator to a driven body;
An output roller attached to the output shaft of the actuator;
A driven body side roller in contact with the driven body, and a plurality of rollers.
The plurality of rollers have output shafts arranged at different positions with respect to the first direction, and the output shaft of the first roller of the plurality of rotors is given a force in the first direction, and the first roller A driving force transmission structure in which a force in a second direction opposite to the first direction is applied to the output shaft of the second roller adjacent to the first roller . The driving force transmission structure according to claim 1,
The plurality of rollers are in contact with each other, the distance from the rotation center to the outer periphery when the driving force is transmitted,
Equal to the pitch circle radius of the gear when the driving force is transmitted from the actuator to the driven body in a gear train including a plurality of gears;
A driving force transmission structure characterized by The driving force transmission structure according to claim 1 or 2 ,
The outer periphery of the roller is a rubber member;
A driving force transmission structure characterized by The driving force transmission structure according to any one of claims 1 to 3 ,
A plurality of the rollers are provided with a pressing mechanism for applying a force in a direction to increase a vertical drag generated at a contact portion of the rollers adjacent to each other;
A driving force transmission structure characterized by An optical apparatus comprising the driving force transmission structure according to any one of claims 1 to 4 .

Images